Many illnesses require patients to be confined to hospital beds for extended periods of time. It is often critical to monitoring a patient's medical condition to have information about changes in their weight.
Unfortunately, all prior art systems known for monitoring the weight of a patient have drawbacks.
The preferred way of determining the weight of a patient is to have them stand or sit on a scale. For many patients with severe medical conditions this is not possible as they cannot leave their bed.
Another alternative is to weigh the bed and the patient together. This is sometimes possible when the patient is confined to a standard hospital bed that has casters. The hospital bed may be moved over a scale mounted in the floor and weighed periodically. This approach has very limited accuracy however, because the hospital bed usually weighs several times more than the patient. The scales that are available for weighing such heavy loads are often not sufficiently accurate for medical diagnostic purposes.
Some special beds have been designed to enable weighing of a patient therein. These beds are very expensive. In addition, such systems are complex and may be subject to failure. Due to the costs associated with these special weighing beds there is usually an insufficient number of these available for the number of patients who would benefit from accurate weighing on a frequent basis.
Most hospitals already have a large number of standard movable beds. These beds include four casters which include large wheels that enable the bed to be moved about the hospital either with or without a patient therein. It would be desirable to be able to use these standard portable beds for purposes of weighing a patient.
Standard hospital beds are subject to rough service environments. This is due to the fact that they are often pushed over floors, curbs and elevator openings while carrying heavy loads. In addition, they are often subject to rough treatment during movement when patients are not confined therein. Such treatment can result in large transient loads as well as vibration. These conditions have made it impractical to mount sensors on conventional hospital beds because available sensors would tend to be damaged.
Similarly it is also often desirable to weigh patients who are confined to a chair for a medical procedure. Currently available systems are not well suited to this purpose.
Thus, there exists a need for a system that is inexpensive and reliable and can be installed on a hospital bed or chair and is capable of accurately determining a patient's weight. There further exists a need for a system which may retrofitted to existing hospital beds to enable the portable bed to be used to accurately weigh patients confined thereto.